Geography
Dr Andy Ridgwell
BA(Cantab), MSc(Nott), PhD(EAnglia)
Royal Society University Research Fellow
Leader of BRIDGE
Contact
Office: G10aN
Tel: +44 (0)117 954 6858
Fax: +44 (0)117 9287878
Email: andy.ridgwell@bristol.ac.uk
Research interests
Changes in atmospheric CO2 and the strength of 'Greenhouse' warming appear central to why the Earth was subject to glaciation and ice ages at some points in the past but sweltered in a 'hot house' during others. Rather more 'catastrophic' events have also occurred, when the geological record suggests a massive release of CO2 took place, perhaps due to the oxidation of methane unlocked from ocean sediments. One such event occurred at the end of an Epoch known as the Palæocene, some 10 million years after the last dinosaur walked on the face of the Earth. Because there was a substantial warming of the Earth's surface at this time as well as species extinctions in the deep ocean there may be important lessons to be learnt about the consequences of our continued burning of fossil fuels and increasing global warming. But first we need to understand what the source and quantity of the carbon was as well as what causes CO2 to vary through geologic time in general.
We do not have spare copies of our planet on which to experiment and test ideas about the causes of global change and how atmospheric CO2 is regulated! Computer models of the Earth system - the suite of interacting physical, chemical, and biological (and human processes) that, in transporting and transforming materials and energy jointly determine climate and the conditions for life, are therefore essential. I work mainly with the GENIE model, which includes representations of ocean circulation and, greenhouse warming, sea ice, and vegetation on land, as well as all their interactions. To this I have added the cycles of carbon and nutrients within the ocean and how this interacts with the climate system and with the sedimentary reservoirs of the deep ocean, allowing me to evaluate both past and future controls on atmospheric CO2 and importance of feedbacks in the climate system.
Selected publications
Ridgwell, AJ, Singarayer, JS, Hetherington, AM & Valdes, PJ. 'Tackling Regional Climate Change By Leaf Albedo Bio-geoengineering', Current Biology, 19, (pp. 1-5), 2009. ISSN: 0960-9822 10.1016/j.cub.2008.12.025
Panchuk, KM, Ridgwell, AJ & Kump, LR. 'Sedimentary response to Paleocene Eocene Thermal Maximum carbon release: A model-data comparison', Geology, 36, (pp. 315-318), 2008. ISSN: 0091-7613
Ridgwell, AJ, Kennedy, MJ & Caldeira, K. 'Carbonate Deposition, Climate Stability, and Neoproterozoic Ice Ages', Science, 302 (5646), (pp. 859-862), 2003. ISSN: 0036-8075 10.1126/science.1088342
Watson, AJ, Bakker, DCE, Ridgwell, AJ, Boyd, PW & Law, CS. 'Effect of iron supply on Southern Ocean CO2 uptake and implications for glacial atmospheric CO2', Nature, 407, (pp. 730-733), 2000. ISSN: 0028-0836